Realizing excellent cycle stability of Zn/Na_(3)V_(2)(PO_(4))_(3)batteries by suppressing dissolution and structural degradation in non-aqueous Na/Zn dual-salt electrolytes  

Na/Zn双离子无水电解液抑制材料溶解及结构坍塌,助力卓越循环能力的Zn/Na_(3)V_(2)(PO_(4))_(3)电池

作　　者：Qian Li Kaixuan Ma Cheng Hong Gongzheng Yang Chengxin Wang 李乾;马凯旋;洪城;杨功政;王成新(State Key Laboratory of Optoelectronic Materials and Technologies,School of Materials Science and Engineering,Sun Yat-sen University,Guangzhou 510275,China;The Key Laboratory of Low-carbon Chemistry&Energy Conservation of Guangdong Province,Sun Yat-sen University,Guangzhou 510275,China)

机构地区：[1]State Key Laboratory of Optoelectronic Materials and Technologies,School of Materials Science and Engineering,Sun Yat-sen University,Guangzhou 510275,China [2]The Key Laboratory of Low-carbon Chemistry&Energy Conservation of Guangdong Province,Sun Yat-sen University,Guangzhou 510275,China

出　　处：《Science China Materials》2021年第6期1386-1395,共10页中国科学（材料科学（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(91963210,U1801255,and 51872340);the Fundamental Research Funds for the Central Universities,China(18lgpy06).

摘　　要：The low-cost and high-safety rechargeable zincion batteries(ZIBs)show promising applications for largescale energy storage.However,the(de)intercalation of divalent zinc ions with high charge density restricts cathode materials’choice.Na_(3)V_(2)(PO_(4))_(3)(NVP)is one of the sodium(Na)super-ionic conductor materials that shows feasible utilization in aqueous ZIBs but universally has poor cycle life,commonly limited to 200 cycles or less.In this study,we investigate the capacity degradation mechanism of NVP systematically and then propose a novel organic dual-salt electrolyte to realize excellent cycling stability.We find a spontaneous dissolution of NVP when immersed in the static aqueous electrolyte,and there is an irreversible phase change during the first discharge process,leading to a fast capacity fading in aqueous electrolytes.The dissolution problem can be effectively suppressed by non-aqueous Zn^(2+)-containing electrolytes.However,the sluggish reaction of Zn^(2+)intercalation into NVP causes poor reversibility.We develop a non-aqueous Na/Zn hybrid system by adding Na^(+)ions as charge carriers to address this issue.Highly reversible co-insertion of Na/Zn ions into the NVP enables a high capacity of 84 mA h^(−1)and an outstanding lifetime of 600 cycles at 500 mA g^(−1)without capacity loss.This work provides valuable views on the NVP’s failure mechanisms that will be helpful for ZIB development.开发高性能正极材料是限制锌离子电池发展的重要因素.Na_(3)V_(2)(PO_(4))_(3)(NVP)是一种典型NASICON结构的材料,其作为锌离子电池正极材料具有较高的工作电压,然而其循环性能较差,通常仅200圈.本文首次系统地研究了该材料储锌性能的衰退机理.研究表明,在水系电解液中NVP的自发溶解及首圈放电过程中材料的不可逆相变是其容量衰退的主要原因.采用含锌有机电解液虽可避免其溶解,但锌离子的嵌入易导致晶体结构的坍塌.本文首次引入钠离子作为新的载流子并构建有机Na/Zn混合离子电解液.其中,两种金属离子在NVP中高度可逆的共插层反应助力Zn/Na_(3)V_(2)-(PO_(4))_(3)电池实现了84 mA h g^(−1)的较高容量以及在大电流密度下循环600圈容量零衰减的高稳定性.

关 键 词：energy storage Zn battery Na_(3)V_(2)(PO_(4))_(3) Na/Zn dualsalt electrolyte long life 

分 类 号：TM912[电气工程—电力电子与电力传动] TQ131.12[化学工程—无机化工]